The invention relates to a transformer winding form with a unique and innovative insertion-type leader frame which can be fitted onto the body of the transformer winding form. The leader frame is not only resistant to loosening, but also has a larger and more solid soldering area, thereby increasing the permanent implacement characteristics. As a result, the transformer winding form herein meets the requirements of different electronic components, has a lower overall physical height and accommodates the utilization of an increased number of different soldering methods, and the transformer winding coil equipped therewith possesses such advantages as installation convenience, mechanical stability and the capacity to be wound in an automatic coil winding machine.
Most conventional transformers of this type are used in laptop computers, signal transmission in communications products, power supplies and other microelectronic products. The words winding form, in this context, refer specifically to the unwound inductor section of a transformer surrounding an iron core. An example of a commonly known miniature transformer winding form is illustrated in FIG. 7, wherein the body of the form (2a) is first constructed out of injected plastic or bakelite. One end of a circle terminal (1a) is stamped to form a semi-circular tip (4a) or a flat hook-shaped tip, with the semi-circular tip (4a) or flat hook-shaped tip for subsequent insertion into the circle terminal mounting hole (3a) on the form (2a) manually or by a simple tool which facilitates firm anchoring. However, the mounting hole (3a) created to seat the circle terminal (1a) on the winding form is often too large, resulting in the impossibility of tightly seating the circle terminal (1a), and also is easily enlarged even further which causes additional loosening, especially when this type of winding form is soldered into a PC (printed circuit) board, in which case the winding form may often fall off, and make it impossible to attain full transformer efficiency. On the other hand, the mounting hole (3a) produced may be too small, then in addition to causing difficult insertion of the circle terminal (1a), a problem which is compounded, if an accessory tool is utilized to force insertion, because use of the insertion tool might easily result in nicking the surface of the body of the form (2a), shortening the service life and resulting in a poor quality appearance. Therefore, the conventional fabrication of the circle terminal of this type of winding form is not an ideal design. Moreover, use of such a circle terminal may result in inadequately built-up soldering welds due to the small surface area of the circle terminal (1a), causing poor electrical characteristics and unstable mechanical structure.